Printrbot Jr Heated bed upgrade

12 March 2013 at 9:46 pm

I was so happy when my Printrbot Jr heated bed kit arrived, but it works far from optimal. I didn't expect to be able to print any bigger with this upgrade, only to enable ABS printing and maybe sticking the first layer down a little easier. Instead, I actually got less space to print on despite the huge 6x6 heated bed PCB.

The problem is where the heated bed is positioned. Here's a video highlighting the problems with this $65 kit.

It's not set to be centred on the 6x6, but rather towards the far Y-edge of the platform. The result of these misplaced holes is that I'm actually loosing 1,5 centimetres print area along the Y-axis since the print head may hit the bolts holding the PCB heater.

Another couple things that make me suspect the kit have been made in a hurry, is the metric machine screws that should hold the PCB in place. These are too short to reach through both the PCB and the plywood. The instructions are also unclear about the need for an extra PSU. It says that you should not use the "laptop power supply" that came with the printer. Mine didn't come with a "laptop" PSU but rather a huge 300W ATX supply. I assume this is good enough to drive both the printer and the bed.

Kapton

I also bought a nicely cut 6x6 sheet of Kapton tape. I love the quality of it (feels thick and solid) but I can't get over the fact that you can buy a 100 feet roll of 6" kapton on Ebay for less than the price of a single sheet from Printrbot. Given that you have to manually cut off those nicely rounded corners to make the sheet fit between the bolts that hold the PCB, it's even less of a value. If there was holes cut for these, I could see the value but I think I'll just pick up some 6" kapton and place it next to the 20" kapton I use for the Ultimaker.

The above probably makes you think that I'm not too happy with my purchase, but that's not the case. For it's price, the Printrbot is a really good kit and I dig hacking my printer to make it better. The fan-holder I added helps immensely on the quality of PLA prints. My next upgrades will be some belt tighteners and a better suited industrial PSU that I can fit beneath the printer.

I really feel that all the Printrbot's I've seen have some unpolished edges that could be smoothed quickly. If Printrbot / Brook want's to stay in the 3DP business for a long time, he should look to companies like Ultimaker, RepRap Pro and Makergear. They don't churn out lots of new products, but rather listen to the customers about what must be fixed for the existing kits to be really good. Printrbot is on the right track by adding necessities like fan holders, belt tighteners and this HBP kit.

I think it is now time to polish the three kits (LC, Jr & Plus) to perfection. There's no better advertising then happy customers that has a printer that "just works".